Numerous types of firing devices and systems have been developed and are being used that are suitable for firing or initiating a wide range of explosive devices, such as, for example, shock tubes and blasting caps. A typical firing system is provided with an electrical energy storage device, such as a capacitor, which stores the electrical energy needed to initiate or fire the device. Many such firing devices are also provided with a delay or a countdown circuit that may be set by a user to delay the initiation (i.e., firing) of the device for some period of time after the system is armed. Alternatively, the firing system may be actuated by remote means, such as, for example, via a radio signal.
Unfortunately, however, such firing systems are not without their problems. For example, many firing systems begin charging the electrical energy storage device (e.g., a capacitor) directly in response to a user input (e.g., when the user initiates the countdown). However, if the selected countdown time is relatively long, such a control schedule means that the electrical energy storage device may be charged for a time period that is considerably longer than the countdown time. Consequently, the firing system will be capable of initiating the device well in advance of the desired time, which can lead to pre-mature firings and can present problems if the user decides to abort the countdown.
In addition, while many firing systems are used in carefully controlled environments wherein a user will have ample time to ensure the proper setting and operation of the firing system, other environments, such as law-enforcement and/or military environments, often do not lend themselves to the careful and considered use of such devices. Consequently, there is a continuing need to ensure that such firing systems are easy to use and operate, while minimizing the chances for mis-programming and/or undesired results if time is short.